1. Field of Invention
The present invention relates in general to print transfers using sublimation dyes, and in particular to a pressing apparatus and method of making sublimation dye transfers from color video system prints and effectively applying such prints to coated ceramic mugs, tiles or coated metal articles, or like articles.
2. State of the Art
Methods and various types of Apparatus for producing photographic-like images on hard surfaces such as ceramic mugs and tiles are commercially available to fulfill an existing need evident from the large number of decorated mugs and tiles sold and on sale in a wide variety of consumer retail outlets. These products are currently manufactured by utilizing pre-print transfers, such as decals, in most, if not all, cases which are produced by employing one of the following methods: silk screen printing, offset printing, gravure printing or mimeograph, the inks being used in these processes containing sublimable dyes. These methods require color separation and, in view of economic considerations, relatively long production runs. Another known process uses transfers produced on a xerographic type copy machine, but these transfers are limited to monotones, that is, a single color or black on white. These known transfer systems are not used, as a practical matter, for producing single, one-of-a-kind full color transfers or at least are not economically so used, and currently, other than the instant invention, the only commercially viable method for producing such one-of-a-kind colored ceramic mugs is by hand painting individual pieces.
Today's color video print systems employ primary thermal printing of sublimable dyes that have previously been applied on webs by known techniques. These webs contain successive blocks of yellow, magenta and cyan dyes which are thermally transferred onto print papers specially treated to accept and absorb the sublimable dyes. Information on such printing techniques is disclosed in U.S. Pat. No. 4,650,494, issued Mar. 17, 1987, to Kutsukake et al and U.S. Pat. No. 4,731,091, issued Mar. 15, 1988, to Majima. For the sublimable dyes to be absorbed and provide an image on the reception medium, which is resistent both to wear and fading or color distortion on exposure to daylight or artificial lighting, that medium is provided with a coating of, or is a composition of, or has mixed within its body materials of the types disclosed by Davis, U.S. Pat. No. 4,395,263 of Jul. 26, 1983; Hi et al, U.S. Pat. No. 4,354,851 of Oct. 19, 1982, and Krajec, U.S. Pat. No. 4,664,672 of May 12, 1987.
The art is redundant with patents disclosing methods and apparatus for primary transfer printing wherein sublimation dyes are affixed by known printing techniques, such as off-set, gavure and silkscreen, to carrier webs or sheets, which, in turn, are applied at various temperatures and onto surfaces of varying compositions. For the most part, this primary printing, using carriers or transfers with the prints thereon, is accomplished by heating the elements of the process to the sublimation temperatures of the dyes at near normal atmospheric pressures. The printed side of the carrier or transfer is placed in contact with the object onto which the image is to be printed while heat is applied to either the transfer, or the material to be printed, or both for relatively short durations, normally from one to ten seconds. With exceptions such as disclosed in U.S. Pat. No. 4,395,263 of Davis which relates to printing on various laminates, U.S. Pat. No. 4,411,667 of Meredith et al of Oct. 25, 1983, and U.S. Pat. No. 4,462,852 of Custor, issued Jul. 31, 1984, addressed to printing on materials passing between rollers, the application of significant pressure has not been considered a crucial factor in the transfer process. However, these latter patents are for primary print transfers. As described in the Meredith et al and Custor patents, pressure is provided to compensate for the extremely short contact period between the carrier web and the surface to receive the image. Davis teaches that a small amount of pressure may be used to control the transfer.